1. Technical Field
Various embodiments of the present disclosure relate to semiconductor technologies and, more particularly, to methods of forming patterns having different critical dimensions (CDs).
2. Related Art
To increase integration density of semiconductor devices comprised of integrated circuits, it may be necessary to reduce an area occupied by a unit cell of the semiconductor devices and to increase the number of discrete devices such as transistors, resistors, capacitors or the like, integrated in a limited area of a semiconductor substrate. Various techniques have been attempted to realize fine pattern structures having a nano-scale critical dimension (CD), that is, a size ranging from a few nanometers to several tens of nanometers.
It is difficult to form nano-scale fine patterns of the semiconductor devices only with a photolithography process. Image resolution limits of lithography apparatuses for the photolithography process may be caused by the nature of optical systems for the photolithography process and wavelengths of lights generated from light sources of the optical systems. Methods of forming the fine patterns through a self-assembly of polymer molecules may be considered as a candidate for overcoming the image resolution limits. However, it is difficult to merely apply a direct self-assembly (DSA) of polymer molecules to methods of forming a plurality of patterns having different pitches for example, different widths or different spaces. Accordingly, it is necessary to further develop the methods of forming fine patterns using DSA of the polymer molecules to overcome the limitations of DSA technology.